Ipomoea nil (PROTA)
Ipomoea nil (L.) Roth
- Protologue: Catal. Bot. 1: 36 (1797).
- Family: Convolvulaceae
- Chromosome number: 2n = 30
- Pharbitis nil (L.) Choisy (1762),
- Ipomoea hederacea Baker & Rendle (1905) non (L.) Jacq. (1787).
- Japanese morning glory, picotee morning glory, white-edge morning glory, blue morning glory (En).
- Liseron fleur bleue, ipomée du Nil, étoile du matin (Fr).
- Campainha azul, corda de viola, corriola, campainha, jetirana (Po).
Origin and geographic distribution
Ipomoea nil originated from tropical America, but has become naturalized in most of the tropics and subtropics, including many countries in Africa. Many cultivars are planted as ornamentals in warm and temperate regions.
The seeds, usually dried and powdered, are widely used as a purgative, both in Africa and Asia. In Nigeria dried leaves are applied to burns. In Gabon the roots are considered toxic.
The seeds are official in the Indian Pharmacopoeia as a purgative and are a substitute for jalap (Ipomoea purga (Wender.) Hayne). In China the seeds, known as ‘Pharbitis Semen’, are regarded as diuretic, anthelminthic and laxative and are prescribed for oedema and constipation, to promote menstruation or cause abortion.
The plant is used as a love charm in northern Nigeria. Ipomoea nil is an attractive plant often grown over fences or trellises for its showy flowers. It is also a weed, e.g. in sugarcane.
Production and international trade
While the seed of Ipomoea nil is widely traded in Asia, no information is available on its importance and trade in Africa. Many cultivars of the species are traded as ornamentals throughout the world.
The seeds at first taste sweetish, then acrid and disagreeable. They contain a fixed oil of unpleasant taste, consisting of glycerides of palmitic acid (6%), stearic acid (20%), arachidic acid (8%), behenic acid (1%), oleic acid (44%), linoleic acid (15%) and linolenic acid (6%). The seeds also contain the phenolic amides pharnilatins A and B, the oleanene-type triterpene glycosides pharbitosides A and B, together with β-sitosterol, β-sitosterol glucoside (daucosterol), caffeic acid, and methyl caffeoate. Further compounds isolated are the phytoestrogens pharsyringaresinol and pharbilignoside, as well as the phenylethanoid glycoside pharbiniloside.
From the crude glycoside resin named pharbitin several compounds have been isolated, including (+)-2-methylbutyric acid, tiglic acid, nilic acid (2-methyl-3-hydroxybutyric acid) and a glycosidic acid named pharbitic acid, a derivative of ipurolic acid. Later pharbitic acids B, C and D were isolated, along with valeric acid and 7 oligoglycosides of hydroxy fatty acid methyl esters. From an ethanol extract of the seed 3 ent-kaurane diterpenoids and 6 ent-kaurane diterpene glycosides, pharbosides A–G, were isolated. Further, the spermidine alkaloid N1,N10-ditigloylspermidine was isolated from the seeds. From the flowers the anthocyanin HBA was isolated, which protects against UV-B. In a study with laboratory rats, it was found that feeding them ethanol extracts of the seeds, but not water extracts, caused significant kidney damage. A root extract was found to suppress the proliferation rate of breast cancer cells and human gastric cancer cells inducing apoptotic cell death in vitro.
A gene isolated from Ipomoea nil, named Pharbitis nil leucine zipper gene (PNZIP), is used in genetic modification of plants, e.g. in the transfer of virus resistance.
Annual herb with bristly-hairy twining stems, up to 5 m long. Leaves alternate, simple; petiole up to 8(–15) cm long, bristly-hairy, with 2 black apical glands; blade ovate to circular in outline, up to 14 cm × 13.5 cm, base cordate, 3-lobed, appressed hairy above and below, apex of lobes acuminate. Inflorescence an axillary lax few-flowered cyme, or flowers solitary; peduncle 4–7(–12) cm long; bracteoles linear to filiform, 5–10 mm long. Flowers bisexual, regular, 5-merous; pedicel up to 12 mm long; sepals linear-lanceolate, 2.2–2.8 cm × 3.5 mm at the base, tapering to the apex, densely hairy with patent bristles at the base; corolla funnel-shaped, showy, 6–7.5 cm long, reddish-purple with paler tube; stamens 5, unequal, inserted near the base of the corolla tube; ovary superior, 2–3(–5)-celled, style slender, stigma 2-globular. Fruit an ovoid to globose capsule, 8–15 mm long, glabrous, long apiculate, enclosed in the unchanged calyx. Seeds up to 6–8 mm × c. 4 mm × c. 3.5 mm, black, puberulous. Seedling with epigeal germination; cotyledons with petiole 1–1.5 cm long; blade 2-lobed, about 2–2.5 cm × 2–2.5 cm, base cordate, apex notched; first leaves cordate, both surfaces bristly hairy, margin entire on the first leaf but toothed or shallowly lobed on the second leaf.
Other botanical information
Ipomoea is a large and complex genus containing 500–600 species of vines and shrubs, widely distributed throughout the tropics and subtropics. Ipomoea nil is closely related to Ipomoea purpurea (L.) Roth, Ipomoea indica (Burm.) Merr. and Ipomoea hederacea Jacq. Specimens of Ipomoea nil have sometimes been wrongly identified as the North American Ipomoea hederacea. Ipomoea nil sometimes hybridizes with Ipomoea purpurea.
Several other Ipomoea spp. are medicinally used in southern tropical Africa.
Ipomoea adenioides Schinz is an erect silky-hairy shrub up to 1.2 m tall with white flowers and occurs in Angola, Namibia, Botswana, Zimbabwe and South Africa. In Namibia a root or fruit infusion is drunk to treat cardiac weakness. After castration, the leaf powder is applied to the scrotum. Raw roots are eaten as a substitute for water.
Ipomoea blepharophylla Hallier f. is a prostrate herb with several stems arising from a large tuber; it has whitish flowers with a darker centre. It is widespread, but not common, throughout tropical Africa, excluding the dry and very humid regions. In eastern DR Congo dried root bark powder is mixed with food to treat malaria. A maceration of the crushed tuber is given as an enema to children to treat belly-ache and to adults to treat amoebiasis. It is also given as a drink to cattle suffering from bloating and wind. The tuber is also chewed to treat swollen glands in the neck and to facilitate the expulsion of the placenta.
Ipomoea crassipes Hook. has erect or prostrate stems from a large tuber, and white to red or purple with white flowers. It occurs in East and southern Africa. In southern Africa a maceration of the tuber is used as an enema to treat dysentery. A paste of the ground aerial parts is applied to skin ailments. Leaves are smoked in a pipe and roots are chewed to treat hiccough.
Ipomoea ommaneyi Rendle has several prostrate stems from a large tuber, and pinkish-red flowers. It occurs in Zambia, Botswana, Zimbabwe and Mozambique. In Zimbabwe an infusion of the tuber is drunk to treat body pain and as an aphrodisiac. A tuber decoction is drunk to treat convulsions. Dried and powdered tuber is eaten in porridge to treat stomach-ache.
In Ipomoea plebeia R.Br. (‘bell vine’) 3 subspecies are recognized, subsp. africana Meeuwse, occurring in north-eastern and southern Africa, subsp. indica Verdc. in India, and subsp. plebeia in Malaysia and Australia. It is an annual herb with twining or prostrate stems and small white flowers sometimes with a dark centre. In Somalia leaves are boiled in water until most water is evaporated, after which the leaves are eaten to treat gastro-intestinal complaints.
Ipomoea prismatosyphon Welw. is an erect shrubby herb up to 1.8 m tall with white to pinkish showy flowers. It occurs from Nigeria south to Angola and in East Africa. In Angola a root decoction is taken to treat stomach-ache.
Ipomoea shirambensis Baker is a large, glabrous woody twiner, with purple flowers, which occurs in Tanzania, Malawi, Zambia, Botswana, Zimbabwe, Mozambique and Transvaal (South Africa). In Tanzania root scrapings are applied to hardened abscesses, or a root infusion is used as a wash.
Ipomoea tenuirostris Steud. ex Choisy is a perennial herb with slender, twining or prostrate stems, occurring in Cameroon, DR Congo, Sudan, Eritrea and Ethiopia southward to Zimbabwe and Mozambique. In DR Congo macerations of the aerial parts of the plant are administered as galactagogue. In East Africa leaves are chewed and applied externally to treat rheumatism.
Ipomoea welwitschii Vatke ex Hallier f. is a perennial herb with a globose tuber and white to pinkish flowers. It occurs in Sudan, Tanzania, and most of southern Africa. In Zimbabwe an infusion of the tuber is drunk to treat abdominal pain.
Growth and development
Induction of flowering in Ipomoea nil is being studied, especially the hormonal control of flower induction at the early stages of growth. Flowering is promoted by high temperatures (c. 30°C) and long nights (c. 18 hours). The blue flowers open in the early morning and turn pink during the day, the process being slower in cooler localities. Leaves of Ipomoea nil are sensitive to ozone, but the sensitivity is not sufficiently to use the plant as an indicator of ozone levels.
Ipomoea nil occurs as a ruderal plant growing on roadsides, in hedges, secondary thickets, or as a weed in fields or gardens.
Propagation and planting
Ipomoea nil is propagated by seed. Seed, pre-soaked for 12 hours in warm water, or scarified, is sown in pots in a nursery in early spring in colder climates. The seed usually germinates in 1–3 weeks at 22°C. Seedlings are extremely sensitive to root disturbance, and should be potted up almost as soon as they germinate. Seedlings are kept in a nursery and planted out into their final positions after the last frost.
As an ornamental Ipomoea nil requires a fertile well-drained loamy soil in a sunny locality.
Ipomoea nil is a widespread and common ruderal plant, and is in no danger of genetic erosion. Small germplasm collections are maintained in the United States at the Plant Genetic Resources Conservation Unit, Griffin, GA, and by several plant breeders.
Many cultivars of morning glories, including Ipomoea nil, have been bred, e.g. in Japan, and forms with large flowers in a variety of flower colours now exist. Well-known cultivars include 'Scarlet O'Hara', 'Early Call', and 'Rose Silk'. Ornamental hybrids have also been developed and include 'Imperial Japanese Morning Glory', 'Cameo Elegance', 'Sunrise Serenade' and 'Chocolate Beauty'.
The traditional medicinal uses and numerous bioactive compounds warrant further research of its pharmacological properties and toxicology, as well as its potential role in the process of genetic modification of plants. Ipomoea nil is likely to remain an important ornamental plant.
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- Ju, J.H., Jeon, M.J., Yang, W., Lee, K.M., Seo, H.S. & Shin, I., 2011. Induction of apoptotic cell death by Pharbitis nil extract in HER2-overexpressing MCF-7 cells. Journal of Ethnopharmacology 133(1): 126–131.
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- Zhang, C., Song, Y., Jiang, F., Li, G., Jiang, Y., Zhu, C. & Wen, F., 2012. Virus resistance obtained in transgenic tobacco and rice by RNA interference using promoters with distinct activity. Biologia Plantarum 56(4): 742–748.
- L.P.A. Oyen, PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
Correct citation of this article
Oyen, L.P.A., 2013. Ipomoea nil (L.) Roth. In: Schmelzer, G.H. & Gurib-Fakim, A. (Editors). Prota 11(2): Medicinal plants/Plantes médicinales 2. PROTA, Wageningen, Netherlands. Accessed 5 June 2023.
- See this page on the Prota4U database.